Question

A cart of weight $10N$ is pulled $1.2m$ up a ramp. Force of $5N$ is applied parallel to the ramp. The cart was raised $0.5m$ above its initial level. Calculate the percentage efficiency of the work.

• A. 83.33%
• B. 85%
• C. 84.5%
• D. 86.33%

Answer 1

The correct option is A

83.33%

Given:
Weight of the cart = $\text{10 N}$
Vertical height = $\text{0.5 m}$
Energy output = Potential energy
$PE=m\times g\times h=10\times 0.5=5J$
Energy input = Work done to move the cart
$=\text{Force}\times \text{displacement}$
$=5\times 1.2=6J$
$\text{Percentage efficiency}$ $=\frac{\text{Energy output}}{\text{Energy input}}$ = $\frac{5}{6}$ $\times 100$
$\text{= 83.33}$ %